%% Choix de LaTeX
verbatimtex
%&latex
\documentclass[a4paper]{article}
\usepackage[latin1]{inputenc}
\usepackage[frenchb]{babel}
\begin{document}
etex
%%[geometrie]
input constantes;
input geometriepoint;
beginfig(1);
  affixe.O(u*(3,1));
  label.lrt(btex $O$ etex,z.O);
  path cer;
  cer=cercle(O,3cm);
  draw cer;
  affixe.A(point(0.1*length cer) of cer);
  affixe.B(2[z.A,z.O]);%Symétrique de A par rapport à O
  croix(A);
  croix(B);
  croix(O);
  affixe.C(z.A rotatedabout(z.O,90));
  croix(C);
  draw triangle(A,B,C);
  affixe.F(z.B shifted(z.C-z.O));
  affixe.E(z.A shifted(z.C-z.O));
  draw droite(E,F,1.25);
  label.top(btex $(d'')$ etex,1.25[z.F,z.E]);
  draw droite(E,A,1.25);
  label.rt(btex $(d)$ etex,1.25[z.A,z.E]);
  draw droite(B,F,1.25);
  label.rt(btex $(d')$ etex,1.25[z.B,z.F]);
  label.rt(btex $A$ etex,z.A);
  label.lft(btex $B$ etex,z.B);
  label.top(btex $C$ etex,z.C);
  label.rt(btex $E$ etex,z.E);
  label.lft(btex $F$ etex,z.F);
endfig;
end